Image display incorrect on toolstrip

I use a 32-bit image & use it as a value for Image property of ToolStripButton. But I don't know why it displays unlike the original one. This is the screenshot:

http://img4.imageshack.us/img4/7668/34711开发者_开发百科163.png http://img4.imageshack.us/img4/7668/34711163.png

And my project: http://www.mediafire.com/?3mzmf5r5nnx

Please help me to find the reason. Thanks.

I've opened the 'button_9.png' in Paint.NET and it seems like the 'white glass' of the magnifier is semi-transparent.

So you have to edit the image that the magnifier has an opaque backcolor.